Multiple spindle dividing head

ABSTRACT

A multiple spindle dividing head in which each spindle is driven in synchronism from a common drive shaft adapted to be driven from a single source of power which may be pneumatic, hydraulic or electrical, the spindles being moved automatically from an open to a closed work-piece engaging position by pneumatic or hydraulically actuated means which maintain the spindles in the closed position as they are rotated and yet permit the spindles to be readily opened in any rotative position to release the work-pieces engaged thereby.

BACKGROUND OF THE INVENTION

The present invention relates to dividing or indexing heads by means ofwhich a work-piece may be indexed or rotated by predetermined equalamounts so that various milling, drilling, shaping or planing operationsmay be performed on the work-piece. In particular, the present inventionis directed to a multiple spindle dividing head by means of which aplurality of work-pieces may be acted upon simultaneously.

Dividing heads have been in use for many years and generally comprise awork-piece engaging chuck or collet which is mounted to be eithermanually or mechanically rotated to achieve the desired indexing of thework-piece. Most of the chucks or collets must be manually operated toengage and release the work-piece. While it has hitherto been proposedto provide chucking devices having multiple spindles, and to utilizehydraulic means to cause a collet to grip a work-piece, the prior artdevices have been of complex and expensive construction, and aredifficult to service and maintain in proper adjustment.

SUMMARY OF THE INVENTION

In accordance with the present invention, any desired number of spindlesmay be mounted in either horizontal or vertical alignment in asupporting housing to provide a self-contained operating unit which maybe readily mounted on a fixed base or on a swivel base or otheradjustable support by means of which the spindles may be accuratelypositioned relative to a bank of cutting tools, drills or the like,which will act upon the work-pieces engaged by the spindles.

The spindles are adapted to be rotated in unison by means of a commondrive shaft connected through a suitable clutch to a shaft rotatingactuator which may comprise an pneumatic or hydraulic actuator, or anelectronic stepping motor, the actuator being chosen in accordance withavailable sources of power. Many plants are equipped with hydraulicand/or pneumatic systems which may be utilized to supply fluid pressureboth for the actuator and for the collet locking means, each spindlehaving a split ring collet at its leading end projecting from thehousing.

The collets are axially movable relative to the spindles from an open orwork-piece receiving position to a closed or work-piece engagingposition by means of sets of hydraulic or pneumatic pistons which actagainst face plates by means of which the collets are displaced intogripping engagement with the work-pieces, the face plates serving tomaintain the collets in tight gripping engagement with the work-piecesuntil pressure on the sets of pistons is relieved, whereupon the colletswill be returned to their open position.

The mechanism of the present invention is of simple construction and itis easy to adjust and repair, and yet is rugged and accurate inoperation.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a multiple spindle dividing head inaccordance with the invention, with certain parts broken away and othersin dotted line.

FIG. 2 is a plan view of the device with the cover removed and withcertain parts shown in dotted lines.

FIG. 3 is an enlarged horizontal sectional view taken along the line3--3 of FIG. 1 illustrating the spindle with the collet in the open orwork-piece receiving position.

FIG. 4 is a vertical sectional view similar to FIG. 3 but illustratingthe collet in the closed or workpiece engaging position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 illustrate a dividing head having four spindles, althoughit will be understood that the number of spindles may be varied asrequired. The spindles are mounted in a rectangular housing, indicatedgenerally at 1, the housing preferably being of box-like constructionfabricated from steel plate and having a bottom 2 mounting a rear wall3, opposing end walls 4 and 5, and an enlarged front wall 6, togetherwith a removable cover 7 by means of which access may be readily had tothe interior of the housing. A spindle supporting wall 8 extendslengthwise of the housing intermediate the front and rear walls to whichthe spindles, indicated generally at 9, are rotatably mounted by meansof bearing assemblies 10.

Each of the spindles 9 mounts a bevel driving gear 11 engaged by a bevelgear 12 mounted on a drive shaft 13 extending lengthwise of the housingin parallel relation to supporting wall 8, the drive shaft beingjournaled at one end in bushing 14 mounted in end wall 5 and at itsopposite end in an over-run clutch 15 mounted on end wall 4.

The drive shaft 13 is rotated by an actuator 16, which may comprise arotary cylinder of known construction, which rotates shaft 13 throughover-run clutch 15 to which the actuator 16 is operatively connectedthrough translation coupling 17. As previously indicated, the actuator16 may be pneumatically or hydraulically controlled, or it may comprisean electronic stepping motor, the function of the actuator being toindex the spindles through the desired degree of rotation each time theactuator is energized. For example, if it is desired to rotate thespindles through an angle of 90°, the actuator, if it comprises a rotarycylinder, will be adjusted to rotate the drive shafts 13 through therequired number of revolutions to effect a 90° rotation of each spindle.The actuator may be manually actuated or it may be operated by a timingdevice or limit switches, depending upon the nature of the operationbeing performed and the equipment by which it is performed.

Each of the spindles mounts a collet 18 having a tapered head 19 andthree equally spaced slots 20 (FIG. 1) which split the head intosections, together with a central work-piece receiving opening 21. Thecollets extend through horizontal bores 22 in enlarged front wall 6 andhave their tapered heads 19 rotatably journaled in bearing collars 23surrounding the outermost ends of bores 22, the bearing collars 23having tapered shoulders 24 (FIGS. 3 and 4) adapted to bear against thetapered heads of the collets.

As also seen in FIGS. 3 and 4, a fitting 26 is threaded to the oppositeend of collet 18, the fitting having an annular shoulder 27 againstwhich a thrust bearing 28 is seated, the thrust bearing, which may beplastic, providing a seat for the annular face plate 29 which surroundsand is rotatable on fitting 26. Fitting 26 also mounts a rearwardlyprojecting shaft 30, preferably of rectangular configuration, which isslidably received in a mating socket 31 in spindle 9, a coil spring 32being seated in socket 31 in abutting engagement with the end of shaft30. The collet 18 is thus operatively connected to spindle 9 and willrotate therewith, the collet additionally being displaceable axiallyrelative to the spindle.

Axial displacement of the collet is accomplished by a pair of pistons 33and 34 fitted in cylinder-forming annular bores 35 and 36, respectively,formed in front wall 6 on opposite sides of collet 18, the bores beingclosed at their outermost ends by fittings 37 and 38 through whichpiston rods 39 and 40 project, the ends of the piston rods contactingface plate 29 adjacent its opposite side edges. Coil springs 41 and 42surround the piston rods 39 and 40, respectively, and extend between thepistons at one end and the fittings at the opposite end, the springsnormally biasing the pistons to a retracted position. Fluid underpressure is adapted to be introduced into the ends of thecylinder-forming bores 35 and 36 through branch passages 43 and 44 boredin the front wall 6 in prolongation of the cylinder forming bores, thepassages 43 and 44 interconnecting with vertical passages 45 and 46,respectively, which, as seen in FIGS. 1 and 2, connect with main supplypassage 47 which extends lengthwise through front wall 6 and isconnected to a source of supply, represented by the conduit 48. Thus,fluid under pressure introduced into main supply line 47 will flowthrough the sets of vertical passageways 45, 46 and the branchpassageways 43, 44 to displace the pistons 33, 34 outwardly against thecompression of springs 35, 36, the piston rods 39, 40 thus bearingagainst and displacing face plate 29 rearwardly relative to front wall6.

FIG. 4 illustrates the collet assembly in the rearwardly displacedposition in which it will be seen that the tapered head 19 of the collethas traveled inwardly along the tapered shoulders 24, thereby radiallycompressing the head of the collet inwardly so as to contract theopening 21 and hence exert tight gripping engagement on the work-piece49 inserted in the opening 21. Axial displacement of the collet alsoserves to displace the shaft 30 inwardly in socket 31 against thetension of spring 32; and the parts will be maintained in the displacedposition until the fluid pressure on pistons 33 and 34 is released. Whenthe fluid pressure is released, the springs 35 and 36 will displace thepistons to their fully retracted position and the piston rods 39 and 40will retract, thereby freeing the face plate 29 and the collet 18 foroutward movement relative to front wall 6 under the influence ofcompressed spring 32, the parts thereby returning to the positionillustrated in FIG. 3 in which the sections of the collet will be freeto expand radially outwardly to the open position.

It is preferred to provide a plunger 50 in the work-piece receivingopening 21 in the collet, the plunger being biased in the direction ofthe work-piece by a spring member 51. With this arrangement, when awork-piece is positioned in each collet, a pusher bar or similararrangement may be employed to uniformly position the outermost endedges of the work-pieces even though their over-all lengths may varyslightly due to manufacturing tolerances. If desired, and as illustratedin FIG. 1, a work-piece guide 52 may be mounted in front of the collets18, the guide having V-grooves 53 which will accurately align thework-pieces with the openings 21 in the collets.

As should now be evident, in the operation of the device, thework-pieces will be inserted, either manually or automatically, into thecollets and seated against the plungers 50 in desired alignment.Thereafter, fluid under pressure will be introduced through conduit 48to actuate the sets of pistons 33, 34 which act through face plates 29to displace the collets rearwardly, thereby forcing the collets intogripping engagement with the work-pieces. Suitable valve means or othercontrols will be provided to introduce the fluid under pressure into thesystem; and such control means may be manually actuated or automaticallyactuated in conjunction with the feeding and positioning of thework-pieces. Once the work-pieces have been engaged, an initialoperation may be performed on them or they may be rotated to a desiredstarting position. As previously described, the acutator 16 will beactuated to effect the desired indexing movement of the collets, thespindles 9 acting to rotate the collets through interconnecting shafts30, the spindles rotating in their bearings 10 and the collets in theirbearing assemblies 23. By reason of the face plates 29, which bearagainst thrust bearing 28, the collets are maintained in their axiallydisplaced work-piece engaging position irrespective of the rotationalposition of the collets. As should also be evident, the construction isquite simple, yet efficient, and readily lends itself to productionmanufacture. For example, the various bores and fluid passageways may bereadily formed in front wall 6 by straight-line drilling and tappingoperations, as may be the mounting of the spindles to the supportingwall 8 using readily available bearing assemblies. With the removablecover, all parts of the device are readily accessible for adjustment,repair or replacement.

Modifications may be made in the invention without departing from itsspirit and purpose; a number of such modifications have already been setforth and others will undoubtedly occur to the skilled worker in the artupon reading this specification. For example, while in the embodimentillustrated the work-pieces are inserted into the collets from the frontof the device, they could also be inserted from the rear in an automaticfeeding operation of known character, the fitting 26, shaft 30 andspindle 9 being axially bored in alignment with opening 21 in thecollet. Thus, a continuous length of work-piece stock could be fedthrough rear wall 3 for incremental projection from the collets.Accordingly, it is not intended that the scope of the invention belimited other than in the manner set forth in the claims which follow.

The embodiments of the invention in which an exclusive property orprivilege is claimed are described as follows:
 1. A multiple spindledividing head comprising a housing, a plurality of spindles rotatablymounted in said housing, a common drive shaft in said housing, gearmeans operatively connecting said spindles to said drive shaft, actuatormeans operatively connected to said drive shaft for rotating saidspindles, split ring collets having work-piece receiving openingstherein operatively connected to said spindles for rotation therewith,means mounting said collets for axial movement relative to saidspindles, said collets having tapered heads at their forward endsprojecting through openings in said housing, bearing collars mounted onsaid housing and surrounding the heads of said collets, said bearingcollars having tapered surfaces engaging the tapered heads of saidcollets, face plates surrounding said collets, said face plates beingoperatively connected to said collets to displace them axiallyrearwardly, pairs of fluid cylinders on opposite sides of each of saidcollets extending in parallel relation thereto, said cylinderscontaining rearwardly projecting piston rods positioned to contact saidface plates upon movement from a retracted to an extended position, andmeans for supplying fluid under pressure to said cylinders to displacesaid piston rods rearwardly, whereby the tapered heads of the colletsare radially contracted by the tapered surfaces of said bearing collarsas said collets are displaced from a forward work-piece receivingposition to a rearward work-piece clamping position by the piston rodsas they bear against said face places, said face plates permitting saidcollets to rotate while maintained in their work-piece engagingposition.
 2. The dividing head claimed in claim 1 wherein said colletsare in axial alignment with said spindles, and wherein the meansmounting said collets for axial movement relative to said spindlescomprises shafts projecting rearwardly from said collets and sockets insaid spindles positioned to slidably but non-rotatively receive saidshafts.
 3. The dividing head claimed in claim 2 including means biasingsaid collets to their forward position.
 4. The dividing head claimed inclaim 3 wherein the means biasing said collets to their forward positioncomprise springs in said sockets extending between said shafts and theinner ends of said sockets.
 5. The dividing head claimed in claim 4including spring means in said cylinders to bias said piston rods totheir retracted position.
 6. The dividing head claimed in claim 5wherein said housing has a thick wall through which the collet receivingopenings extend, wherein said fluid cylinders are defined by bores insaid thick wall, and wherein the means for supplying fluid underpressure to said cylinders comprise passageways formed in said thickwalls.